Search for features in the spectrum of primordial perturbations using Planck and other datasets

Journal article

We reconstruct the power spectrum of primordial curvature perturbations by applying a well-validated non-parametric technique employing Tikhonov regularisation to the first data release from the Planck satellite. To improve the reconstruction on small spatial scales we include data from the ground-based ACT and SPT experiments, the WiggleZ galaxy redshift survey, the CFHTLenS tomographic weak lensing survey, and spectral analysis of the Lyman-α forest. The reconstructed scalar spectrum (assuming the standard ΛCDM cosmology) is not scale-free but has an infrared cutoff at k ≲ 5 × 10-4 Mpc-1 and several (2-3)σ features, of which two at wavenumber k/Mpc-1 0.0018 and 0.057 had been seen already in WMAP data. A higher significance feature at k ∼ 0.12 Mpc-1 is indicated by Planck data, but may be sensitive to the systematic uncertainty around multipole ℓ ∼ 1800 in the 217×217 GHz cross-spectrum. In any case accounting for the 'look elsewhere' effect decreases its global significance to ∼2σ.

Authors: Hunt, P; Sarkar, S

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: IOP Publishing
• Journal: Journal of Cosmology and Astroparticle Physics
• Volume: 2015
• Issue: 12
• Pages: 052-052
• Publication date: 2015-12-01
• Acceptance date: 2015-12-16
• DOI: 10.1088/1475-7516/2015/12/052
• EISSN: 1475-7516
• Keywords: SBTMR